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BM4400 Spares or Repair

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Craig
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Yarm, United Kingdom
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Craig posted on Tue, Feb 13 2018 10:08 AM

How hard can it be?


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Craig
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Craig replied on Sun, Mar 18 2018 3:31 PM

Soren.....that's very good of you, please let me know how much you want for it and I will arrange for payment.

Regards Craig

 

 

Søren Mexico
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Bad news, opened the BM 4400 yesterday evening, went straight to the switch to check it with my meter, but got funny readings, when switching on-off the ohm jumped while switching but in both positions showed mega ohms. I left it there until today and took out the switch


Collecting Vintage B&O is not a hobby, its a lifestyle.

Søren Mexico
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I cleaned the switch and worked it some 50 times but it still didnt work, cleaned again and worked it, and at last the switch blade came out

Here close up

Here where it came from

And here what it looked like when I finished. I dont recommend changing this switch if avoidable, its a big PIB to change it.

 

Collecting Vintage B&O is not a hobby, its a lifestyle.

Beo_Jean
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Beo_Jean replied on Mon, Mar 19 2018 11:08 PM

Thanks a lot Soren for the pictures.

Confirms to me that the switch needs an spark killer capacitors and explains why this common failure.

Craig
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Craig replied on Tue, Mar 20 2018 5:23 PM

Soren my friend.....that's a massive amount of work you undertook on my behalf, I don't know what to say.........I really appreciate you doing this. And I have to say looking at where you got to and what it took to get there I can only agree with your advice not to try and change this switch. Even changing the whole assembly would be an exercise in itself.... I will reconsider the position over a glass of wine, I suggest you join me after all you have done Beer

Søren Mexico
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I done it before, back in 2012 i think,

 


Collecting Vintage B&O is not a hobby, its a lifestyle.

Craig
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Yes.....I remember reading your post detailing that total strip down, your a hero to take it on a second time Thumbs Up.

Ok fortified by the glass of wine that Soren should have drank I removed the back and had another look, note the missing solder tab bottom right that came apart when the wire was unsoldered.....I stupidly lost it, thinking the switch is totally wrecked anyway.


Craig
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When testing for continuity across the two left hand side connectors I noticed I had good contact when the central slider was stopped from moving completely into the bottom position, the picture shows the switch in the OFF position, when in the ON position the slider is at the bottom of its slot.


Craig
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Ever optimistic I have fashioned a new solder tab from an old relay base and have epoxy glued it into place.


Craig
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I know it all looks a little "Heath Robinson" but when in Rome, and with wine 


Craig
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And with a small wedge of plastic epoxy'd in place....


Søren Mexico
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If it works, looks doesnt matter, only you and I will know Smile

Collecting Vintage B&O is not a hobby, its a lifestyle.

Craig
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Soren....I dont know what to say, tested the switch out with a multimeter and both poles are working fine.....I'm not confident such a repair will last the test of time but for now it looks good.


Craig
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Power switch OFF


Craig
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Power switch ON.......I feel so guilty for putting Soren to so much trouble and then fixing the switch myself, however long it lasts I feel I should have tried harder before agreeing to let someone spend so much time....sorry Soren Embarrassed


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